Infant screen media usage and social-emotional functioning.

There has been little research on whether and how screen media usage affects social-emotional (SE) function prior to two years of age, even though early SE development is understood to be nurtured through interpersonal experience, mainly withthe primary caregiver. This study sought to characterise infant screen media usage and understand how it may link with concurrent SE function by testing associated effects on reducing parent-infant interaction and of parent psychological factors. Questionnaire responses from 327 UK-based parents of infants aged 6-24 months showed diverse usage in the amount of time spent on screen media ('screen time') and amount of parental involvement (co-sharing and co-referencing). Infants with possible SE delay experienced more screen time than those at low risk. The study tested three mediation models and found support for the displacement and not distancing hypothesis based on this community sample. While screen time predicted both SE competence and SE problems, reduced parent-infant play partially mediated the effect on SE competence. Parent depressed mood was positively linked with infant SE problems, but there was little evidence that increased screen time mediated this effect. Also, parent reflective function and attitudes toward parent-infant play were unrelated to screen time. Though longitudinal study is warranted, the findings implicate screen media usage as potentially directly and indirectly relevant when addressing infant mental health.

Strength and endurance training reduces the loss of eccentric hamstring torque observed after soccer specific fatigue.

OBJECTIVES: To investigate the effect of two hamstring training protocols on eccentric peak torque before and after soccer specific fatigue. PARTICIPANTS: Twenty-two university male soccer players. DESIGN: Isokinetic strength tests were performed at 60°/s pre and post fatigue, before and after 2 different training interventions. A 45-min soccer specific fatigue modified BEAST protocol (M-BEAST) was used to induce fatigue. Players were randomly assigned to a 4 week hamstrings conditioning intervention with either a maximum strength (STR) or a muscle endurance (END) emphasis. MAIN OUTCOME MEASURES: The following parameters were evaluated: Eccentric peak torque (EccPT), angle of peak torque (APT), and angle specific torques at knee joint angles of 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° and 90°. RESULTS: There was a significant effect of the M-BEAST on the Eccentric torque angle profile before training as well as significant improvements in post-fatigue torque angle profile following the effects of both strength and muscle endurance interventions. CONCLUSIONS: Forty-five minutes of simulated soccer activity leads to reduced eccentric hamstring torque at longer muscle lengths. Short-term conditioning programs (4-weeks) with either a maximum strength or a muscular endurance emphasis can equally reduce fatigue induced loss of strength over this time period.